import {
  FileLoader,
  Loader,
  Texture
} from "../../build/three.module.js";

var TGALoader = function (manager) {

  Loader.call(this, manager);

};

TGALoader.prototype = Object.assign(Object.create(Loader.prototype), {

  constructor: TGALoader,

  load: function (url, onLoad, onProgress, onError) {

    var scope = this;

    var texture = new Texture();

    var loader = new FileLoader(this.manager);
    loader.setResponseType('arraybuffer');
    loader.setPath(this.path);
    loader.setWithCredentials(this.withCredentials);

    loader.load(url, function (buffer) {

      texture.image = scope.parse(buffer);
      texture.needsUpdate = true;

      if (onLoad !== undefined) {

        onLoad(texture);

      }

    }, onProgress, onError);

    return texture;

  },

  parse: function (buffer) {

    // reference from vthibault, https://github.com/vthibault/roBrowser/blob/master/src/Loaders/Targa.js

    function tgaCheckHeader(header) {

      switch (header.image_type) {

        // check indexed type

        case TGA_TYPE_INDEXED:
        case TGA_TYPE_RLE_INDEXED:
          if (header.colormap_length > 256 || header.colormap_size !== 24 || header.colormap_type !== 1) {

            console.error('THREE.TGALoader: Invalid type colormap data for indexed type.');

          }

          break;

        // check colormap type

        case TGA_TYPE_RGB:
        case TGA_TYPE_GREY:
        case TGA_TYPE_RLE_RGB:
        case TGA_TYPE_RLE_GREY:
          if (header.colormap_type) {

            console.error('THREE.TGALoader: Invalid type colormap data for colormap type.');

          }

          break;

        // What the need of a file without data ?

        case TGA_TYPE_NO_DATA:
          console.error('THREE.TGALoader: No data.');

        // Invalid type ?

        default:
          console.error('THREE.TGALoader: Invalid type "%s".', header.image_type);

      }

      // check image width and height

      if (header.width <= 0 || header.height <= 0) {

        console.error('THREE.TGALoader: Invalid image size.');

      }

      // check image pixel size

      if (header.pixel_size !== 8 && header.pixel_size !== 16 &&
        header.pixel_size !== 24 && header.pixel_size !== 32) {

        console.error('THREE.TGALoader: Invalid pixel size "%s".', header.pixel_size);

      }

    }

    // parse tga image buffer

    function tgaParse(use_rle, use_pal, header, offset, data) {

      var pixel_data,
        pixel_size,
        pixel_total,
        palettes;

      pixel_size = header.pixel_size >> 3;
      pixel_total = header.width * header.height * pixel_size;

      // read palettes

      if (use_pal) {

        palettes = data.subarray(offset, offset += header.colormap_length * (header.colormap_size >> 3));

      }

      // read RLE

      if (use_rle) {

        pixel_data = new Uint8Array(pixel_total);

        var c, count, i;
        var shift = 0;
        var pixels = new Uint8Array(pixel_size);

        while (shift < pixel_total) {

          c = data[offset++];
          count = (c & 0x7f) + 1;

          // RLE pixels

          if (c & 0x80) {

            // bind pixel tmp array

            for (i = 0; i < pixel_size; ++i) {

              pixels[i] = data[offset++];

            }

            // copy pixel array

            for (i = 0; i < count; ++i) {

              pixel_data.set(pixels, shift + i * pixel_size);

            }

            shift += pixel_size * count;

          } else {

            // raw pixels

            count *= pixel_size;

            for (i = 0; i < count; ++i) {

              pixel_data[shift + i] = data[offset++];

            }

            shift += count;

          }

        }

      } else {

        // raw pixels

        pixel_data = data.subarray(
          offset, offset += (use_pal ? header.width * header.height : pixel_total)
        );

      }

      return {
        pixel_data: pixel_data,
        palettes: palettes
      };

    }

    function tgaGetImageData8bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image, palettes) {

      var colormap = palettes;
      var color, i = 0, x, y;
      var width = header.width;

      for (y = y_start; y !== y_end; y += y_step) {

        for (x = x_start; x !== x_end; x += x_step, i++) {

          color = image[i];
          imageData[(x + width * y) * 4 + 3] = 255;
          imageData[(x + width * y) * 4 + 2] = colormap[(color * 3) + 0];
          imageData[(x + width * y) * 4 + 1] = colormap[(color * 3) + 1];
          imageData[(x + width * y) * 4 + 0] = colormap[(color * 3) + 2];

        }

      }

      return imageData;

    }

    function tgaGetImageData16bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {

      var color, i = 0, x, y;
      var width = header.width;

      for (y = y_start; y !== y_end; y += y_step) {

        for (x = x_start; x !== x_end; x += x_step, i += 2) {

          color = image[i + 0] + (image[i + 1] << 8); // Inversed ?
          imageData[(x + width * y) * 4 + 0] = (color & 0x7C00) >> 7;
          imageData[(x + width * y) * 4 + 1] = (color & 0x03E0) >> 2;
          imageData[(x + width * y) * 4 + 2] = (color & 0x001F) >> 3;
          imageData[(x + width * y) * 4 + 3] = (color & 0x8000) ? 0 : 255;

        }

      }

      return imageData;

    }

    function tgaGetImageData24bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {

      var i = 0, x, y;
      var width = header.width;

      for (y = y_start; y !== y_end; y += y_step) {

        for (x = x_start; x !== x_end; x += x_step, i += 3) {

          imageData[(x + width * y) * 4 + 3] = 255;
          imageData[(x + width * y) * 4 + 2] = image[i + 0];
          imageData[(x + width * y) * 4 + 1] = image[i + 1];
          imageData[(x + width * y) * 4 + 0] = image[i + 2];

        }

      }

      return imageData;

    }

    function tgaGetImageData32bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {

      var i = 0, x, y;
      var width = header.width;

      for (y = y_start; y !== y_end; y += y_step) {

        for (x = x_start; x !== x_end; x += x_step, i += 4) {

          imageData[(x + width * y) * 4 + 2] = image[i + 0];
          imageData[(x + width * y) * 4 + 1] = image[i + 1];
          imageData[(x + width * y) * 4 + 0] = image[i + 2];
          imageData[(x + width * y) * 4 + 3] = image[i + 3];

        }

      }

      return imageData;

    }

    function tgaGetImageDataGrey8bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {

      var color, i = 0, x, y;
      var width = header.width;

      for (y = y_start; y !== y_end; y += y_step) {

        for (x = x_start; x !== x_end; x += x_step, i++) {

          color = image[i];
          imageData[(x + width * y) * 4 + 0] = color;
          imageData[(x + width * y) * 4 + 1] = color;
          imageData[(x + width * y) * 4 + 2] = color;
          imageData[(x + width * y) * 4 + 3] = 255;

        }

      }

      return imageData;

    }

    function tgaGetImageDataGrey16bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {

      var i = 0, x, y;
      var width = header.width;

      for (y = y_start; y !== y_end; y += y_step) {

        for (x = x_start; x !== x_end; x += x_step, i += 2) {

          imageData[(x + width * y) * 4 + 0] = image[i + 0];
          imageData[(x + width * y) * 4 + 1] = image[i + 0];
          imageData[(x + width * y) * 4 + 2] = image[i + 0];
          imageData[(x + width * y) * 4 + 3] = image[i + 1];

        }

      }

      return imageData;

    }

    function getTgaRGBA(data, width, height, image, palette) {

      var x_start,
        y_start,
        x_step,
        y_step,
        x_end,
        y_end;

      switch ((header.flags & TGA_ORIGIN_MASK) >> TGA_ORIGIN_SHIFT) {

        default:
        case TGA_ORIGIN_UL:
          x_start = 0;
          x_step = 1;
          x_end = width;
          y_start = 0;
          y_step = 1;
          y_end = height;
          break;

        case TGA_ORIGIN_BL:
          x_start = 0;
          x_step = 1;
          x_end = width;
          y_start = height - 1;
          y_step = -1;
          y_end = -1;
          break;

        case TGA_ORIGIN_UR:
          x_start = width - 1;
          x_step = -1;
          x_end = -1;
          y_start = 0;
          y_step = 1;
          y_end = height;
          break;

        case TGA_ORIGIN_BR:
          x_start = width - 1;
          x_step = -1;
          x_end = -1;
          y_start = height - 1;
          y_step = -1;
          y_end = -1;
          break;

      }

      if (use_grey) {

        switch (header.pixel_size) {

          case 8:
            tgaGetImageDataGrey8bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image);
            break;

          case 16:
            tgaGetImageDataGrey16bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image);
            break;

          default:
            console.error('THREE.TGALoader: Format not supported.');
            break;

        }

      } else {

        switch (header.pixel_size) {

          case 8:
            tgaGetImageData8bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image, palette);
            break;

          case 16:
            tgaGetImageData16bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image);
            break;

          case 24:
            tgaGetImageData24bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image);
            break;

          case 32:
            tgaGetImageData32bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image);
            break;

          default:
            console.error('THREE.TGALoader: Format not supported.');
            break;

        }

      }

      // Load image data according to specific method
      // var func = 'tgaGetImageData' + (use_grey ? 'Grey' : '') + (header.pixel_size) + 'bits';
      // func(data, y_start, y_step, y_end, x_start, x_step, x_end, width, image, palette );
      return data;

    }

    // TGA constants

    var TGA_TYPE_NO_DATA = 0,
      TGA_TYPE_INDEXED = 1,
      TGA_TYPE_RGB = 2,
      TGA_TYPE_GREY = 3,
      TGA_TYPE_RLE_INDEXED = 9,
      TGA_TYPE_RLE_RGB = 10,
      TGA_TYPE_RLE_GREY = 11,

      TGA_ORIGIN_MASK = 0x30,
      TGA_ORIGIN_SHIFT = 0x04,
      TGA_ORIGIN_BL = 0x00,
      TGA_ORIGIN_BR = 0x01,
      TGA_ORIGIN_UL = 0x02,
      TGA_ORIGIN_UR = 0x03;

    if (buffer.length < 19) console.error('THREE.TGALoader: Not enough data to contain header.');

    var content = new Uint8Array(buffer),
      offset = 0,
      header = {
        id_length: content[offset++],
        colormap_type: content[offset++],
        image_type: content[offset++],
        colormap_index: content[offset++] | content[offset++] << 8,
        colormap_length: content[offset++] | content[offset++] << 8,
        colormap_size: content[offset++],
        origin: [
          content[offset++] | content[offset++] << 8,
          content[offset++] | content[offset++] << 8
        ],
        width: content[offset++] | content[offset++] << 8,
        height: content[offset++] | content[offset++] << 8,
        pixel_size: content[offset++],
        flags: content[offset++]
      };

    // check tga if it is valid format

    tgaCheckHeader(header);

    if (header.id_length + offset > buffer.length) {

      console.error('THREE.TGALoader: No data.');

    }

    // skip the needn't data

    offset += header.id_length;

    // get targa information about RLE compression and palette

    var use_rle = false,
      use_pal = false,
      use_grey = false;

    switch (header.image_type) {

      case TGA_TYPE_RLE_INDEXED:
        use_rle = true;
        use_pal = true;
        break;

      case TGA_TYPE_INDEXED:
        use_pal = true;
        break;

      case TGA_TYPE_RLE_RGB:
        use_rle = true;
        break;

      case TGA_TYPE_RGB:
        break;

      case TGA_TYPE_RLE_GREY:
        use_rle = true;
        use_grey = true;
        break;

      case TGA_TYPE_GREY:
        use_grey = true;
        break;

    }

    //

    var useOffscreen = typeof OffscreenCanvas !== 'undefined';

    var canvas = useOffscreen ? new OffscreenCanvas(header.width, header.height) : document.createElement('canvas');
    canvas.width = header.width;
    canvas.height = header.height;

    var context = canvas.getContext('2d');
    var imageData = context.createImageData(header.width, header.height);

    var result = tgaParse(use_rle, use_pal, header, offset, content);
    getTgaRGBA(imageData.data, header.width, header.height, result.pixel_data, result.palettes);

    context.putImageData(imageData, 0, 0);

    return canvas;

  }

});

export {TGALoader};
